Work over the past year has extended previous studies on gonococcal surface charge properties that result from expression of certain lipooligosaccharide molecules and outer membrane proteins and possible roles that these charge characteristics play in the pathobiological abilities of Opa+ organisms. Of particular recent interest is the susceptibilities of gonococci that express different porin and Opa proteins in their outer membrane to polysulfated compounds such as heparin. The Por1A form of porin enables non-piliated gonococci to adhere to and be taken up by tissue culture cells even when the bacteria do not express an Opa protein, but when non-piliated gonococci express Por1B, they do not adhere to epithelial cells unless they express certain Opa proteins. Both systems appear to employ heparan sulfate proteoglycans of the eukaryotic ells. We find that susceptibilities of gonococci to growth inhibition by heparin depend on both porin and Opa phenotypes and the results are quite novel. Opa- Por1A organisms are more liable to heparin than Opa- Por1B cells; but when the organisms express an Opa protein, Por1A organisms become more susceptible to heparin whereas Por1B bacteria become less susceptible. These results suggest cooperative but divergent effects of porin and Opa polypeptides on their interactions with polysulfated compounds. - Neisseria gonorrhea, bacterial cell charge, outer membrane porin proteins, outer membrane Opa proteins, heparin